When a pneumatic radial tire for aircraft rolls over a foreign object that has fallen onto the runway, a cut may occur in the tread. If the cut reaches the belt or the carcass, the tire may puncture, or the tread rubber may detach from the tire starting at the cut.
To address this problem, a technique is proposed in Patent Literature 1, for example, to provide a crown protective layer between the belt layer and the tread. The crown protective layer is formed from a wavy cord layer composed of wavy cords arranged in parallel and an organic fiber cord layer located further outward in the tire radial direction than the wavy cord layer, composed of organic fiber cords arranged in parallel, and extending in a straight line either in the circumferential direction of the tread or at an angle with respect to the circumferential direction of the tread. When damage to the tread is received, the wavy cord layer inhibits the damage from reaching through to the belt layer, and after damage to the tread, the organic fiber cord layer inhibits cracks from spreading in the circumferential direction along the bottom of tread grooves.
FIG. 5 is a partial developed plan view schematically showing the belt structure of the above-described tire. As shown in FIG. 5, the amplitude center line of one of the wavy cords, indicated by the alternate long and short dash line, is substantially parallel to the equatorial surface of the tire. Therefore, if rubber becomes detached at the interface between these cords and the rubber layer located on the outer periphery thereof, the detachment extends along the cords in the circumferential direction of the tire, thus increasing the size of the detached rubber fragment and running the risk of the fragment damaging the body of the aircraft, for example by colliding against the aircraft.